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Experiments with Hierarchical Inverse Dynamics Controllers on a Torque Controlled Humanoid


Conference Paper



We expect autonomous legged robots to perform complex tasks in persistent interaction with an uncertain and changing environment (e.g. in a disaster relief scenario). Therefore, we need to design algorithms that can generate precise but compliant motions while optimizing the interactions with the environment. In this context, torque control algorithms often offer high performance for motion control while guaranteeing a certain level of compliance. In addition they allow for direct control of interaction forces with the environment. Recent contributions have demonstrated the relevance of torque con- trol approaches for humanoid robots, for example for balanc- ing capabilities [5, 6]. Among those we find passivity-based approaches [5] that regulate the position of the Center of Mass (CoM) by applying admissible contact forces under the quasi- static assumption. On the one hand, these approaches do not rely on a precise dynamic model of the robot while natu- rally guaranteeing robustness due to the passivity property of the controller. On the other hand the quasi-static assumption might be limiting for dynamic motions. A promising way of leveraging this limitation are control algorithms that take the full dynamic model into account [6]. However, the need for a precise dynamic model, sensor noise (particularly in the ve- locities) and limited torque bandwidth makes them more chal- lenging to implement. Moreover, it is generally required to simplify the optimization process to meet time requirements of fast control loops (typically 1 kHz on modern torque con- trolled robots). Practical evaluations of both approaches are still rare due to the lack of torque controlled humanoid plat- forms and the complexity in conducting such robot experiments.

Author(s): Herzog, A. and Righetti, L. and Grimminger, F. and Schaal, S.
Book Title: Proceedings of Dynamic Walking
Year: 2014

Department(s): Autonomous Motion, Movement Generation and Control
Bibtex Type: Conference Paper (inproceedings)

Address: Zürich, Switzerland
Cross Ref: p10590
Language: English
Note: clmc
URL: http://www-clmc.usc.edu/publications/H/herzog-DW2014.pdf

Links: PDF


  title = {Experiments with Hierarchical Inverse Dynamics Controllers on a Torque Controlled Humanoid},
  author = {Herzog, A. and Righetti, L. and Grimminger, F. and Schaal, S.},
  booktitle = {Proceedings of Dynamic Walking},
  address = {Zürich, Switzerland},
  year = {2014},
  note = {clmc},
  crossref = {p10590},
  url = {http://www-clmc.usc.edu/publications/H/herzog-DW2014.pdf}